Like Paul, Ammon equates Yahweh with the pagan deity. Despite the real differences, the important resemblance is that Yahweh occupies the same place in the conceptual universe. Lamoni was probably a polytheist with his Great Spirit considered to be the highest ranking of the multiple gods.
Lamoni also expresses bewilderment about “the heavens.” This must be seen as a comment on Ammon’s religious terminology, not our understanding of “the heavens” as the night sky. Ammon apparently thought of heaven as a multiple or layered (hence, plural) place, not simply as a place where Yahweh resides.